New to me is the yeti and it’s systems.

The Sat nav has my current position some 7 miles out.

HW- Version: H04

SW- Version: 5238

Map version HDD: 8536

 

I Appreciate you help.

My RNS510B started did this, it would eventually work out the error on longer journeys however it was the start of the end for the unit which totally failed a short time later. 

GPS aerial knackered possibly water ingress.

I had this on a brand new octavia vrs ,when I looked on the briskoda  forum it was a well known issue something like Hamburg syndrome or some other German town and was fixed with a new gps antenna I the head unit I believe,so as previous post says antenna knackered.